DOCSLIB.ORG

Distributed Computer Systems

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Distributed Computer Systems 10/8/15! DISTRIBUTED COMPUTER SYSTEMS MESSAGE ORIENTED COMMUNICATIONS Dr. Jack Lange Computer Science Department University of Pittsburgh Fall 2015 Outline n" Message Oriented Communication n" Sockets and Socket API n" Message Passing Interface – MPI n" Architecture and Design Issues n" Message Oriented Persistent Communication n" Message Queues n" IBM WebSphereMQ n" Stream Oriented Communication n" Continuous Media Requirements n" Flow Specification and QoS Support n" Delay and Jitter Control n" Packet Loss Control n" Conclusion 1! 10/8/15! MESSAGE ORIENTED COMMUNICATION SOCKETS Sockets n" A Socket is a communication end point n" Processes can send and Host or Host or Server receive messages to and Server from its socket n" Abstraction over the Process Controlled by Process Application communication end point socket Developer socket that is by the local OS for a TCP with TCP with specific transport protocol buffers, Internet buffers, variables variables n" Sending process relies on transport infrastructure which brings message to socket at receiving process 2! 10/8/15! Socket Arguments – Protocol n" Function socket – int socket ( int family, int type, int protocol) n" Return > 0 if success and -1 if error Family! Type! Protocol! Actual Protocol! AF_INET! SOCK_DGRAM! IPPROTO_UDP! UDP! AF_INET! SOCK_STREAM! IPPROTO_TCP! TCP! AF_INET! SOCK_RAW! IPPROTO_ICMP! ICMP! AF_INET! SOCK_RAW! IPPROTO_RAW! raw IP! Sockets Creation n" The system call socket() is used to create a new socket n" Int sockfd = socket(PF_INET, SOCK_STREAM, 0); n" PF_INET = Protocol Family (Internet) n" SOCK_STREAM = TCP n" TCP is a reliable protocol n" SOCK_DGRAM = UDP n" UDP is a “best effort” protocol, no guaranteed reliability 3! 10/8/15! Overview of the Sockets Interface Client! Server! Socket() Socket() Bind() open_listenfd open_clientfd Listen() Connection! Request! connect Accept() Client! Write() Read() Server! Await connection! Session! request from! read() write() next client! EOF! Close() Read() Close() MESSAGE ORIENTED COMMUNICATION MESSAGE PASSING INTERFACE 4! 10/8/15! What is MPI? n" A message-passing library specifications for parallel computers, clusters, and heterogeneous networks n" Extended message-passing model n" Communication modes n" Standard, synchronous, buffered, and ready. n" Designed for parallel applications and tailored to transient communications n" Provides access to advanced parallel hardware n" It assumes that serious failures are fatal and do not require automatic recovery n" For example, process crashes or network disconnect Group and Context n" MPI assumes communication takes place with a group of processes – (groupID, procID) n" Use in lieu of a transport-level address n" MPI ties the concepts of process group and communication context into a communicator ! ! Group! Context! ! ! Communicator 5! 10/8/15! MPI Abstractions n" A process group is high-level abstraction, visible to users n" A context is a system-defined object that uniquely identifies a communicator – Mechanism to isolate messages in distinct libraries and the user programs from one another n" A message sent in one context can't be received in other contexts. n" The communication context is low-level abstraction, not visible to users n" A communicator is a data object that specializes the scope of a communication. n" MPI_COMM_WORLD is an initial communicator, which is predefined and consists of all the processes running when program execution begins MPI Communication Semantics n" Point-to-point communication is the basic concept of MPI standard and fundamental for send and receive operations for typed data with associated message tag. n" Using the point-to point communication, messages can be passed to another process with explicit message tag and implicit communication context. n" Each process can carry out its own code in MIMD style, sequential or multi-threaded. n" MPI is made thread-safe by not using global state. 6! 10/8/15! MPI Communication Primitives Primitive Meaning MPI_bsend Append outgoing message to a local send buffer MPI_send Send a message and wait until copied to local or remote buffer MPI_ssend Send a message and wait until receipt starts MPI_sendrecv Send a message and wait for reply MPI_isend Pass reference to outgoing message, and continue MPI_issend Pass reference to outgoing message, and wait until receipt starts MPI_recv Receive a message; block if there are none MPI_irecv Check if there is an incoming message, but do not block MESSAGE ORIENTED COMMUNICATION MESSAGE QUEUING SYSTEMS 7! 10/8/15! Message-Queuing Model n" MQM, aka Message Oriented Middleware, provides support for persistent asynchronous communication n" MOM offers intermediate-term message storage capacity, without requiring either the sender of receiver to be active Sender Running! Sender Running! Sender Passive! Sender Passive! Receiver Running! Receiver Passive! Receiver Running! Receiver Passive! MOM Basic Semantics and Interface n" MOM supports loosely-coupled in time semantics n" Senders are given only guarantees that message will eventually be inserted in the receiver’s queue n" No guarantee about if or when will messages be read n" Recipient-behavior dependent n" Basic interface to a queue in a message-queuing system. Primitive Meaning Put Append a message to a specified queue Get Block until the specified queue is nonempty, and remove the first message Poll Check a specified queue for messages, and remove the first. Never block. Install a handler to be called when a message is put into the specified Notify queue. 8! 10/8/15! MQM General Architecture n" Source and destination queues are distributed across multiple machines n" The relationship between queue-level addressing and network-level addressing. MQM Generalized Architecture – Routers n" The general organization of a message-queuing system with routers. 2-29! 9! 10/8/15! Message Brokers n" Common message format, typically used in traditional networks, does not generally work for MQM systems n" Mostly due to the diversity of applications, which reduces the best common format to a sequence of bytes n" Brokers – Message broker in a message-queuing system. MQM Brokers Functionalities n" Message brokers act as an application-level gateway n" Their main purpose is to convert incoming messages to a format that can be understood by the recipient n" Properly match end-of-record delimiters between database applications n" More advanced broker are designed to handle conversations between two different database applications n" Difficult task, as information and semantic “mapping” between two different applications may not always be possible n" Brokers are commonly used in Enterprise Application Integration for mediation n" Publish/Subscribe is the typical communication model n" Brokers “matches” messages to applications’ interests 10! 10/8/15! WebSphere MQ – MQ Example n" General organization of IBM's WebSpher MQ message-queuing system – Queue Managers (QM), Message Channels (MC), and Message Channel Agents (MCA) 2-31! WebSphereMQ MCs and MCAs n" Message channels are an abstraction of transport level connections. n" A MC is a unidirectional, reliable connection between a sending and a receiving QM n" Internet-based MCs are implemented as TCP connections n" The two ends of a MC are managed by a MCA Attribute Description Transport type Determines the transport protocol to be used FIFO delivery Indicates that messages are to be delivered in the order they are sent Message length Maximum length of a single message Setup retry Specifies maximum number of retries to start up the remote MCA count Delivery retries Maximum times MCA will try to put received message into queue 11! 10/8/15! WebSphereMQ Message Transfer n" Generalized organization queuing network using routing tables and aliases. n" Routing Table Entry: <DestMQ, sendQ>, where DestMQ is the name of the destination QM and senQ is the name of the local send queue Message Transfer Primitives n" WebSphereMQ Message Queue Interface Primitives Primitive Description MQopen Open a (possibly remote) queue MQclose Close a queue MQput Put a message into an opened queue MQget Get a message from a (local) queue 12! 10/8/15! MESSAGE ORIENTED COMMUNICATION STREAM ORIENTED COMMUNICATION Stream Communication Model n" Support for data streams, time-dependent information such as audio and video, requires communication models that go beyond those that support independent and complete units of information General Architecture for Streaming Stored Media over a Network! 13! 10/8/15! Data Streams – Point-to-Point n" Setting up a stream directly between two devices. 2-35.2! Data Streams -- Multicasting n" An example of multicasting a stream to several receivers. 14! 10/8/15! Streams, flows and QoS n" The Quality of Service (QoS) of an application is the “look and feel” of how the stream will flow n" QoS Support depends on two components n" Specification of the flow/stream n" Enforcing the QoS requirements specification of the supported flows n" The QoS support implementation depends on many, many factors, n" It may require the “Flow Admission Protocol” n" Given a new flow specifications, and a set of currently supported flows, a decision has to be made whether the new flow is to be accepted or rejected Streams and Quality of Service n" QoS Flow Specification Parameters n" The required bit rate at which data should be transported. n" The maximum delay until a session has been set up n" The maximum end-to-end delay . n" The maximum delay variance, or jitter. n" The maximum round-trip delay. 15! 10/8/15! QoS
Load more

Recommended publications
  • Efficient Inter-Core Communications on Manycore Machines
    ZIMP: Efficient Inter-core Communications on Manycore Machines Pierre-Louis Aublin Sonia Ben Mokhtar Gilles Muller Vivien Quema´ Grenoble University CNRS - LIRIS INRIA CNRS - LIG Abstract—Modern computers have an increasing num- nication mechanisms enabling both one-to-one and one- ber of cores and, as exemplified by the recent Barrelfish to-many communications. Current operating systems operating system, the software they execute increasingly provide various inter-core communication mechanisms. resembles distributed, message-passing systems. To sup- port this evolution, there is a need for very efficient However it is not clear yet how these mechanisms be- inter-core communication mechanisms. Current operat- have on manycore processors, especially when messages ing systems provide various inter-core communication are intended to many recipient cores. mechanisms, but it is not clear yet how they behave In this report, we study seven communication mech- on manycore processors. In this report, we study seven anisms, which are considered state-of-the-art. More mechanisms, that are considered state-of-the-art. We show that these mechanisms have two main drawbacks that precisely, we study TCP, UDP and Unix domain sock- limit their efficiency: they perform costly memory copy ets, pipes, IPC and POSIX message queues. These operations and they do not provide efficient support mechanisms are supported by traditional operating sys- for one-to-many communications. We do thus propose tems such as Linux. We also study Barrelfish message ZIMP, a new inter-core communication mechanism that passing, the inter-process communication mechanism of implements zero-copy inter-core message communications and that efficiently handles one-to-many communications.
    [Show full text]
  • D-Bus, the Message Bus System Training Material
    Maemo Diablo D-Bus, The Message Bus System Training Material February 9, 2009 Contents 1 D-Bus, The Message Bus System 2 1.1 Introduction to D-Bus ......................... 2 1.2 D-Bus architecture and terminology ................ 3 1.3 Addressing and names in D-Bus .................. 4 1.4 Role of D-Bus in maemo ....................... 6 1.5 Programming directly with libdbus ................. 9 1 Chapter 1 D-Bus, The Message Bus System 1.1 Introduction to D-Bus D-Bus (the D originally stood for "Desktop") is a relatively new inter process communication (IPC) mechanism designed to be used as a unified middleware layer in free desktop environments. Some example projects where D-Bus is used are GNOME and Hildon. Compared to other middleware layers for IPC, D-Bus lacks many of the more refined (and complicated) features and for that reason, is faster and simpler. D-Bus does not directly compete with low level IPC mechanisms like sock- ets, shared memory or message queues. Each of these mechanisms have their uses, which normally do not overlap the ones in D-Bus. Instead, D-Bus aims to provide higher level functionality, like: Structured name spaces • Architecture independent data formatting • Support for the most common data elements in messages • A generic remote call interface with support for exceptions (errors) • A generic signalling interface to support "broadcast" type communication • Clear separation of per-user and system-wide scopes, which is important • when dealing with multi-user systems Not bound to any specific programming language (while providing a • design that readily maps to most higher level languages, via language specific bindings) The design of D-Bus benefits from the long experience of using other mid- dleware IPC solutions in the desktop arena and this has allowed the design to be optimised.
    [Show full text]
  • Beej's Guide to Unix IPC
    Beej's Guide to Unix IPC Brian “Beej Jorgensen” Hall [email protected] Version 1.1.3 December 1, 2015 Copyright © 2015 Brian “Beej Jorgensen” Hall This guide is written in XML using the vim editor on a Slackware Linux box loaded with GNU tools. The cover “art” and diagrams are produced with Inkscape. The XML is converted into HTML and XSL-FO by custom Python scripts. The XSL-FO output is then munged by Apache FOP to produce PDF documents, using Liberation fonts. The toolchain is composed of 100% Free and Open Source Software. Unless otherwise mutually agreed by the parties in writing, the author offers the work as-is and makes no representations or warranties of any kind concerning the work, express, implied, statutory or otherwise, including, without limitation, warranties of title, merchantibility, fitness for a particular purpose, noninfringement, or the absence of latent or other defects, accuracy, or the presence of absence of errors, whether or not discoverable. Except to the extent required by applicable law, in no event will the author be liable to you on any legal theory for any special, incidental, consequential, punitive or exemplary damages arising out of the use of the work, even if the author has been advised of the possibility of such damages. This document is freely distributable under the terms of the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License. See the Copyright and Distribution section for details. Copyright © 2015 Brian “Beej Jorgensen” Hall Contents 1. Intro................................................................................................................................................................1 1.1. Audience 1 1.2. Platform and Compiler 1 1.3.
    [Show full text]
  • An Introduction to Linux IPC
    An introduction to Linux IPC Michael Kerrisk © 2013 linux.conf.au 2013 http://man7.org/ Canberra, Australia [email protected] 2013-01-30 http://lwn.net/ [email protected] man7 .org 1 Goal ● Limited time! ● Get a flavor of main IPC methods man7 .org 2 Me ● Programming on UNIX & Linux since 1987 ● Linux man-pages maintainer ● http://www.kernel.org/doc/man-pages/ ● Kernel + glibc API ● Author of: Further info: http://man7.org/tlpi/ man7 .org 3 You ● Can read a bit of C ● Have a passing familiarity with common syscalls ● fork(), open(), read(), write() man7 .org 4 There’s a lot of IPC ● Pipes ● Shared memory mappings ● FIFOs ● File vs Anonymous ● Cross-memory attach ● Pseudoterminals ● proc_vm_readv() / proc_vm_writev() ● Sockets ● Signals ● Stream vs Datagram (vs Seq. packet) ● Standard, Realtime ● UNIX vs Internet domain ● Eventfd ● POSIX message queues ● Futexes ● POSIX shared memory ● Record locks ● ● POSIX semaphores File locks ● ● Named, Unnamed Mutexes ● System V message queues ● Condition variables ● System V shared memory ● Barriers ● ● System V semaphores Read-write locks man7 .org 5 It helps to classify ● Pipes ● Shared memory mappings ● FIFOs ● File vs Anonymous ● Cross-memory attach ● Pseudoterminals ● proc_vm_readv() / proc_vm_writev() ● Sockets ● Signals ● Stream vs Datagram (vs Seq. packet) ● Standard, Realtime ● UNIX vs Internet domain ● Eventfd ● POSIX message queues ● Futexes ● POSIX shared memory ● Record locks ● ● POSIX semaphores File locks ● ● Named, Unnamed Mutexes ● System V message queues ● Condition variables ● System V shared memory ● Barriers ● ● System V semaphores Read-write locks man7 .org 6 It helps to classify ● Pipes ● Shared memory mappings ● FIFOs ● File vs Anonymous ● Cross-memoryn attach ● Pseudoterminals tio a ● proc_vm_readv() / proc_vm_writev() ● Sockets ic n ● Signals ● Stream vs Datagram (vs uSeq.
    [Show full text]
  • Message Passing Model
    Message Passing Model Giuseppe Anastasi [email protected] Pervasive Computing & Networking Lab. (PerLab) Dept. of Information Engineering, University of Pisa PerLab Based on original slides by Silberschatz, Galvin and Gagne Overview PerLab Message Passing Model Addressing Synchronization Example of IPC systems Message Passing Model 2 Operating Systems Objectives PerLab To introduce an alternative solution (to shared memory) for process cooperation To show pros and cons of message passing vs. shared memory To show some examples of message-based communication systems Message Passing Model 3 Operating Systems Inter-Process Communication (IPC) PerLab Message system – processes communicate with each other without resorting to shared variables. IPC facility provides two operations: send (message ) – fixed or variable message size receive (message ) If P and Q wish to communicate, they need to: establish a communication link between them exchange messages via send/receive The communication link is provided by the OS Message Passing Model 4 Operating Systems Implementation Issues PerLab Physical implementation Single-processor system Shared memory Multi-processor systems Hardware bus Distributed systems Networking System + Communication networks Message Passing Model 5 Operating Systems Implementation Issues PerLab Logical properties Can a link be associated with more than two processes? How many links can there be between every pair of communicating processes? What is the capacity of a link? Is the size of a message that the link can accommodate fixed or variable? Is a link unidirectional or bi-directional? Message Passing Model 6 Operating Systems Implementation Issues PerLab Other Aspects Addressing Synchronization Buffering Message Passing Model 7 Operating Systems Overview PerLab Message Passing Model Addressing Synchronization Example of IPC systems Message Passing Model 8 Operating Systems Direct Addressing PerLab Processes must name each other explicitly.
    [Show full text]
  • Message Passing
    COS 318: Operating Systems Message Passing Jaswinder Pal Singh Computer Science Department Princeton University (http://www.cs.princeton.edu/courses/cos318/) Sending A Message Within A Computer Across A Network P1 P2 Send() Recv() Send() Recv() Network OS Kernel OS OS COS461 2 Synchronous Message Passing (Within A System) Synchronous send: u Call send system call with M u send system call: l No buffer in kernel: block send( M ) recv( M ) l Copy M to kernel buffer Synchronous recv: u Call recv system call M u recv system call: l No M in kernel: block l Copy to user buffer How to manage kernel buffer? 3 API Issues u Message S l Buffer (addr) and size l Message type, buffer and size u Destination or source send(dest, msg) R l Direct address: node Id, process Id l Indirect address: mailbox, socket, recv(src, msg) channel, … 4 Direct Addressing Example Producer(){ Consumer(){ ... ... while (1) { for (i=0; i<N; i++) produce item; send(Producer, credit); recv(Consumer, &credit); while (1) { send(Consumer, item); recv(Producer, &item); } send(Producer, credit); } consume item; } } u Does this work? u Would it work with multiple producers and 1 consumer? u Would it work with 1 producer and multiple consumers? u What about multiple producers and multiple consumers? 5 Indirect Addressing Example Producer(){ Consumer(){ ... ... while (1) { for (i=0; i<N; i++) produce item; send(prodMbox, credit); recv(prodMbox, &credit); while (1) { send(consMbox, item); recv(consMbox, &item); } send(prodMbox, credit); } consume item; } } u Would it work with multiple producers and 1 consumer? u Would it work with 1 producer and multiple consumers? u What about multiple producers and multiple consumers? 6 Indirect Communication u Names l mailbox, socket, channel, … u Properties l Some allow one-to-one mbox (e.g.
    [Show full text]
  • Open Message Queue Technical Overview Release 5.0
    Open Message Queue Technical Overview Release 5.0 May 2013 This book provides an introduction to the technology, concepts, architecture, capabilities, and features of the Message Queue messaging service. Open Message Queue Technical Overview, Release 5.0 Copyright © 2013, Oracle and/or its affiliates. All rights reserved. This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited. The information contained herein is subject to change without notice and is not warranted to be error-free. If you find any errors, please report them to us in writing. If this is software or related documentation that is delivered to the U.S. Government or anyone licensing it on behalf of the U.S. Government, the following notice is applicable: U.S. GOVERNMENT RIGHTS Programs, software, databases, and related documentation and technical data delivered to U.S. Government customers are "commercial computer software" or "commercial technical data" pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, the use, duplication, disclosure, modification, and adaptation shall be subject to the restrictions and license terms set forth in the applicable Government contract, and, to the extent applicable by the terms of the Government contract, the additional rights set forth in FAR 52.227-19, Commercial Computer Software License (December 2007).
    [Show full text]
  • Multiprocess Communication and Control Software for Humanoid Robots Neil T
    IEEE Robotics and Automation Magazine Multiprocess Communication and Control Software for Humanoid Robots Neil T. Dantam∗ Daniel M. Lofaroy Ayonga Hereidx Paul Y. Ohz Aaron D. Amesx Mike Stilman∗ I. Introduction orrect real-time software is vital for robots in safety-critical roles such as service and disaster response. These systems depend on software for Clocomotion, navigation, manipulation, and even seemingly innocuous tasks such as safely regulating battery voltage. A multi-process software design increases robustness by isolating errors to a single process, allowing the rest of the system to continue operating. This approach also assists with modularity and concurrency. For real-time tasks such as dynamic balance and force control of manipulators, it is critical to communicate the latest data sample with minimum latency. There are many communication approaches intended for both general purpose and real-time needs [19], [17], [13], [9], [15]. Typical methods focus on reliable communication or network-transparency and accept a trade-off of increased mes- sage latency or the potential to discard newer data. By focusing instead on the specific case of real-time communication on a single host, we reduce communication latency and guarantee access to the latest sample. We present a new Interprocess Communication (IPC) library, Ach,1 which addresses this need, and discuss its application for real-time, multiprocess control on three humanoid robots (Fig. 1). There are several design decisions that influenced this robot software and motivated development of the Ach library. First, to utilize decades of prior development and engineering, we implement our real-time system on top of a POSIX-like Operating System (OS)2.
    [Show full text]
  • Sarath Singapati Inter Process Communication in Android Master of Science Thesis
    SARATH SINGAPATI INTER PROCESS COMMUNICATION IN ANDROID MASTER OF SCIENCE THESIS Examiner: Professor Tommi Mikkonen Examiner and thesis subject approved by The Faculty of Computing and Electrical Engineering on 7th March 2012 II ABSTRACT TAMPERE UNIVERSITY OF TECHNOLOGY Master’s Degree Programme in Information Technology SARATH SINGAPATI INTER PROCESS COMMUNICATION IN ANDROID Master of Science Thesis, 45 pages, 4 Appendix pages June 2012 Major: Software Systems Examiner: Professor Tommi Mikkonen Keywords: Android, Google, mobile applications, Process, IPC Google's Android mobile phone software platform is currently the big opportunity for application software developers. Android has the potential for removing the barriers to success in the development and sale of a new generation of mobile phone application software. Just as the standardized PC and Macintosh platforms created markets for desktop and server software, Android, by providing a standard mobile phone application environment, creates a market for mobile applications and the opportunity for applica- tions developers to profit from those applications. One of the main intentions of Android platform is to eliminate the duplication of functionality in different applications to allow functionality to be discovered and in- voked on the fly, and to let users replace applications with others that offer similar func- tionality. The main problem here is how to develop applications that must have as few dependencies as possible, and must be able to provide services to other applications. This thesis studies the Android mobile operating system, its capabilities in develop- ing applications that communicate with each other and provide services to other applica- tions. As part of the study, a sample application called “Event Planner”, has been devel- oped to experiment how Inter Process Communication works in Android platform, ex- plains how to implement, and use Inter Process Communication (IPC).
    [Show full text]
  • Message Passing
    Message passing CS252 • Sending of messages under control of programmer – User-level/system level? Graduate Computer Architecture – Bulk transfers? Lecture 24 • How efficient is it to send and receive messages? – Speed of memory bus? First-level cache? Network Interface Design • Communication Model: Memory Consistency Models – Synchronous » Send completes after matching recv and source data sent » Receive completes after data transfer complete from matching send – Asynchronous Prof John D. Kubiatowicz » Send completes after send buffer may be reused http://www.cs.berkeley.edu/~kubitron/cs252 4/27/2009 cs252-S09, Lecture 24 2 Synchronous Message Passing Asynch. Message Passing: Optimistic Source Destination Source Destination (1) Initiate send Recv Psrc, local VA, len (1) Initiate send (2) Address translation on Psrc Send Pdest, local VA, len (2) Address translation (3) Local/remote check Send (P , local VA, len) (3) Local/remote check dest (4) Send-ready request Send-rdy req (4) Send data (5) Remote check for (5) Remote check for posted receive; on fail, Tag match allocate data buffer posted receive Wait Tag check Data-xfer req (assume success) Processor Allocate buffer Action? (6) Reply transaction Recv-rdy reply (7) Bulk data transfer Source VA Dest VA or ID Recv P , local VA, len Time src Data-xfer req Time • More powerful programming model • Constrained programming model. • Wildcard receive => non-deterministic • Deterministic! What happens when threads added? • Destination contention very limited. • Storage required within msg layer? • User/System boundary? 4/27/2009 cs252-S09, Lecture 24 3 4/27/2009 cs252-S09, Lecture 24 4 Asynch. Msg Passing: Conservative Features of Msg Passing Abstraction Destination • Source knows send data address, dest.
    [Show full text]
  • Inter-Process Communication
    QNX Inter-Process Communication QNX IPC 2008/01/08 R08 © 2006 QNX Software Systems. QNX and Momentics are registered trademarks of QNX Software Systems in certain jurisdictions NOTES: QNX, Momentics, Neutrino, Photon microGUI, and “Build a more reliable world” are registered trademarks in certain jurisdictions, and PhAB, Phindows, and Qnet are trademarks of QNX Software Systems Ltd. All other trademarks and trade names belong to their respective owners. 1 IntroductionIntroduction IPC: • Inter-Process Communication • two processes exchange: – data – control – notification of event occurrence IPC Thread Thread Process A Process B QNX IPC 2008/01/08 R08 2 © 2006, QNX Software Systems. QNX and Momentics are registered trademarks of QNX Software Systems in certain jurisdictions NOTES: 2 IntroductionIntroduction QNX Neutrino supports a wide variety of IPC: – QNX Core (API is unique to QNX or low-level) • includes: – QNX Neutrino messaging – QNX Neutrino pulses – shared memory – QNX asynchronous messaging • the focus of this course module – POSIX/Unix (well known, portable API’s ) • includes: – signals – shared memory – pipes (requires pipe process) – POSIX message queues (requires mqueue or mq process) – TCP/IP sockets (requires io-net process) • the focus of the POSIX IPC course module QNX IPC 2008/01/08 R08 3 © 2006, QNX Software Systems. QNX and Momentics are registered trademarks of QNX Software Systems in certain jurisdictions NOTES: API: Application Programming Interface 3 InterprocessInterprocess Communication Communication Topics: Message Passing Designing a Message Passing System (1) Pulses How a Client Finds a Server Server Cleanup Multi-Part Messages Designing a Message Passing System (2) Client Information Structure Issues Related to Priorities Designing a Message Passing System (3) Event Delivery Asynchronous Message Passing QNET Shared Memory Conclusion QNX IPC 2008/01/08 R08 4 © 2006, QNX Software Systems.
    [Show full text]
  • [MS-MQOD]: Message Queuing Protocols Overview
    [MS-MQOD]: Message Queuing Protocols Overview Intellectual Property Rights Notice for Open Specifications Documentation . Technical Documentation. Microsoft publishes Open Specifications documentation (“this documentation”) for protocols, file formats, data portability, computer languages, and standards support. Additionally, overview documents cover inter-protocol relationships and interactions. Copyrights. This documentation is covered by Microsoft copyrights. Regardless of any other terms that are contained in the terms of use for the Microsoft website that hosts this documentation, you can make copies of it in order to develop implementations of the technologies that are described in this documentation and can distribute portions of it in your implementations that use these technologies or in your documentation as necessary to properly document the implementation. You can also distribute in your implementation, with or without modification, any schemas, IDLs, or code samples that are included in the documentation. This permission also applies to any documents that are referenced in the Open Specifications documentation. No Trade Secrets. Microsoft does not claim any trade secret rights in this documentation. Patents. Microsoft has patents that might cover your implementations of the technologies described in the Open Specifications documentation. Neither this notice nor Microsoft's delivery of this documentation grants any licenses under those patents or any other Microsoft patents. However, a given Open Specifications document might be covered by the Microsoft Open Specifications Promise or the Microsoft Community Promise. If you would prefer a written license, or if the technologies described in this documentation are not covered by the Open Specifications Promise or Community Promise, as applicable, patent licenses are available by contacting [email protected].
    [Show full text]